1. Field of the Invention
This invention relates to an ink jet recorder that comprises a print head capable of moving vertically up and down relative to the recording paper, and particularly to an ink jet recorder exhibiting good printing performance irrespective of the vertical position of the print head relative to the recording paper.
2. Description of the Related Art
There are two common types of ink jet recorder, namely the integrated head-ink tank type of recorder wherein a small capacity ink tank is contained integrally in the print head, and the separate head and ink tank type of recorder which comprises a large capacity ink tank positioned independently of the print head and wherein ink is supplied to the print head via a tube from the ink tank. Among the latter type of recorder are those which, in view of design or space considerations, or because of the existence of a plurality of printing areas, comprise a print head that can be moved vertically inside the main recorder unit and thus have its up and down position changed.
In the separate head and ink tank type of recorders having print heads that can be moved up and down, the ink tank is fixed in a stationary position, wherefore, when the vertical position of the print head is changed, the positional relationship in the vertical dimension between the print head and the ink tank changes accordingly. As a result of changes in this positional relationship, the back pressure (water head) acting on the print head varies, which can have an adverse effect on printing performance.